What is Lung Cancer (Large Cell Carcinoma of the Lung)

[Anim 4] Lung cancers are tumours arising from cells lining the airways of the respiratory system.

One type of lung cancer is known as Large Cell Carcinoma. The cells of this tumour appear large and abnormal under the microscope.

Statistics on Lung Cancer (Large Cell Carcinoma of the Lung)

Lung cancer is common. One in every 28 Australians will develop lung cancer during their lifetime. Lung cancer is also deadly: it is the commonest cause of cancer death in Australia, accounting for around 23% of male and 15% of female cancer deaths.

Lung cancer is more than twice as common in men as in women.

Geographically, the tumour is found worldwide, but it is especially common in countries with a high tobacco consumption.

Large cell lung cancer is a rare type of lung cancer, accounting for just 9% of all cases of lung cancer.

Risk Factors for Lung Cancer (Large Cell Carcinoma of the Lung)

Cigarette smoking is the main predisposing factor. In recent years, it has been recognised that passive smoking (e.g. from a first degree relative in a house of smokers) can also put people at risk. Generally, the risk increases with the number of cigarettes smoked.

Exposure to asbestos increases the risk of developing this tumour. The combination of asbestos exposure plus cigarette smoking is particularly harmful. Other occupational exposures such as exposure to metals including arsenic, chromium and nickel can also increase risk.

Some studies have suggested that diet can play a role in lung cancer risk. Though it is not known how it works, diets high in fruits and vegetables seem to decrease risk.

Radiation exposure damages the DNA material within the cells and can also cause lung cancer.

Radon (a radioactive gas) exposure from our normal surrounding environment, if higher than normal, can predispose to lung cancer. This evidence is mainly based upon population studies which show that people living in areas with a high radon content are prone to increased incidences of a variety of cancers.

Progression of Lung Cancer (Large Cell Carcinoma of the Lung)

Spread of the tumour can occur by the lymphatic vessels to lymph nodes located within the lung, mediastinum and thorax. If spread by the blood stream, it can lead to deposits of tumour in the liver, opposite lung, bone and brain.

Chest x-ray: lung cancer may be seen on chest x-ray as a solitary pulmonary nodule or mass. As many as 80% of solitary pulmonary nodules (

CT: this is more accurate than chest x-ray, and may be particularly useful in identification of lymph node involvement. See the example image below.

PET scanning can help to distinguish between benign and malignant solitary pulmonary nodules seen on chest x-ray. PET scanning may also be used in the assessment of nodal spread and metastatic disease.

Imaging of other organs: if it is suspected that the cancer has spread to other organs, scans of the liver, brain or bone may be required.While imaging tests are helpful in raising the suspicion of lung cancer, diagnosis requires that cancer cells are seen under a microscope. There are a number of ways of obtaining samples of suspected cancer cells:

Sputum cytology: cells from the sputum (spit) are examined for signs of malignancy (cancer).

Bronchoscopy with washings, brushings and biopsy: a bronchoscopy is a camera tube placed through the throat into the airways of the lungs. Samples of the cells from the airways can be taken with washing, brushing, or biopsy.

Fine needle aspiration biopsy through the skin may be used to investigate suspected lung tumours located on the outside of the lungs.

Prognosis of Lung Cancer (Large Cell Carcinoma of the Lung)

The prognosis (probable outcome) depends on the stage of the tumour. Cancer staging is a tool which allows prediction of patient outcomes, and helps decide on the best treatment options. It takes into account various features of a tumour in an individual patient, which can then be compared to other patients with similar tumour features.

Staging of large cell carcinoma of the lung is based on the TNM (Tumour, Node, Metastasis) system. ‘Tumour’ refers to tumour size, which is measured in centimetres. ‘Node’ refers to the presence of cancerous cells in regional lymph nodes. ‘Metastasis’ refers to the spread of cancer beyond regional lymph nodes to other organs of the body.

Tumour size (T):

Tx: Primary tumour not able to be assessed

T0: No evidence of primary tumour, ie. cancer cells seen on sputum sampling or bronchial washing only

Tis: Carcinoma in situ

T1: Tumour 3 cm or less, surrounded by pleura, without evidence of invasion more proximal than the lobar bronchus.

T2: Tumour with any of the following features:

>3cm in greatest dimension

Involves main bronchus, 2cm or more distal to the carina

Invades visceral pleura

Associated with atelectasis or obstructive pneumonitis, extending to the hilar region but not involving the entire lung.

T3: Tumour of any size,

directly invading the chest wall, diaphragm, mediastinal pleura or parietal pericardium; or tumour in the main bronchus; or

in the main bronchus, less than 2cm distal to the carina, but without involvement of the carina; or

with associated atelectasis or obstructive pneumonitis of the entire lung

T4: Tumour of any size, invading the mediastinum, heart, great vessels, trachea, oesophagus, vertebral body, carina; or with separate tumour nodules in one lobe, or with malignant pleural effusion

M1: Distant metastasis, including separate tumour nodule(s) in a different lobe (ipsi- or contralateral).

Using this classification, non-small cell lung cancers are grouped into stages as follows:

Stage 0: TIS N0 M0

Stage Ia: T1 N0 M0

Stage Ib: T2 N0 M0

Stage IIa: T1 N1 M0

Stage IIb: T2 N1 M0, T3 N0 M0

Stage IIIa: T1 N2 M0, T2 N2 M0, T3 N1 M0, T3 N2 M0

Stage IIIb: any T N3 MO, T4 any N M0

Stage IV: any T any N M1

Using this system, outcomes are best for patients with early stages of disease, with small tumours, no spread to lymph nodes, and no distant spread (metastasis) to other organs. Outcomes are also better for younger patients.

Overall, despite treatment, 5-year survival for all types of lung cancer in Australia is not good: 11% for males and 14% for females. Survival for large cell carcinoma is poorer than that for squamous cell carcinoma and adenocarcinoma, though better than for small cell carcinoma. One estimate places 5-year survival for large cell carcinoma at 11%.

How is Lung Cancer (Large Cell Carcinoma of the Lung) Treated?

Surgery offers the best chance of cure, but is usually only possible with small tumours that have not yet spread (stage I or II). In some cases, lobectomy may be more appropriate than limited resection.

If surgical treatment is to be given, the lymph nodes draining the tumour should be sampled and removed if the cancer has spread.Radiotherapy:

Patients with tumours which are not suitable for surgical resection can benefit from radiotherapy to the chest.

Patients with early disease (Stage I or II cancer) who have had the tumour completely surgically removed do not usually need radiotherapy.

The Cancer Council Australia. ‘Clinical Practice Guidelines for the Prevention, Diagnosis and Management of Lung Cancer’ [online]. National Health and Medical Research Council. 2004. Available at URL: http://www.nhmrc.gov.au/publications (last accessed 1/4/07)